Display hashdigest instead of hash object upon failure.
update changelog and authors file
'pip search' xmlrpc changes in response to pypi changes, http://mail.python.org/pipermail/distutils-sig/2013-May/020888.html
Use git show-ref instead of git branch for better future-proofness.

Based on original patch by Anrs Hu.
break up tests dir into data, unit tests, and functional tests
more functional/unit tests restructure
add back test lost in the restructure
add back in old tox.ini
Merge pull request #962 from qwcode/tests_restructure

Tests restructure
Combine Git get_tag_revs and get_branch_revs into single get_refs method.
Merge branch 'develop' into bugfix-git183-v2

* develop:
  add back in old tox.ini
  add back test lost in the restructure
  more functional/unit tests restructure
  break up tests dir into data, unit tests, and functional tests
bugfix for git 1.8.3, in git 1.8.3 the default branch name is "detached from REVISION" when you `git checkout -q <REVISION>`. If doesn't skip it then `git rev-parse ...` will raise a error while invoking Git._get_revision_from_rev_parse method.
Update changelog and AUTHORS for Git fix.
Merge pull request #967 from carljm/bugfix-git183-v2

Use git show-ref instead of git branch for better future-proofness.
Merge branch '1.3.X' into develop

* 1.3.X:
  Update changelog and AUTHORS for Git fix.
  bugfix for git 1.8.3, in git 1.8.3 the default branch name is "detached from REVISION" when you `git checkout -q <REVISION>`. If doesn't skip it then `git rev-parse ...` will raise a error while invoking Git._get_revision_from_rev_parse method.

Conflicts:
	pip/vcs/git.py
Refactor unpack_http_url.
Cached or already-downloaded files with bad hashes are ignored.
Better interaction between already-downloaded and already-cached.
Add changelog entry.
Fix guessing content-type for already-downloaded file.